JavaScript Alert Message in Response.Write breaking page design in ASP.Net

hello friends,

My problem is that i want to give message after completing any database operation on serverside

 thats why i used to this code

response.write("<script lanuage='javascript'>alert('some message')</script>");

my problem is when i am running my program and after commited operation and getting message structure of my page is changed that means every div boxs and other stuff are automaticly take places randomly on the page.

Please help me what is the actual problem